Seedless and surfactant-free growth of flower-shaped ZnO nanostructures: Growth evolution mechanism

In this work, an innovative seedless and surfactant-free chemical bath deposition (CBD) method at low temperature was applied to obtain flower-shaped ZnO nanostructures (FZONSs) on glass and p-type silicon substrates for the first time. Structural properties of these FZONSs were examined. The NSs were produced from zinc nitrate hexahydrate and hexamethylenetetramine, HMTA solution without any catalyst, template, or seed layer. An electric soldering iron pen was used to simultaneously heat the substrate and aqueous mixture of the constituents to grow the FZONSs. Field emission scanning electron microscopy images of the samples showed the presence of three-dimensional (3D) flower-shaped nanomorphology. Energy-dispersive X-ray spectroscopy detected the right trace elements in the FZONSs. X-ray diffraction analysis of the as-grown samples confirmed the existence of high purity nanocrystalline hexagonal phase of ZnO with preferred growth along (002) lattice planer orientation. The growth of ZnO nanorods into unified flower-like morphology was interpreted using a nucleation dissolution-mediated recrystallization mechanism. The fabricated FZONSs may provide potential in various applications including advanced catalysts, sensing devices, and solar cells.